Pit props



Nov. 3, 1959 K. BARALL 2,911,181

PIT PROPS Original Filed May 23, 1955 19 1.9 gjg wg Ia Q \R Z s ,5 i i,

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, mums Karl Barall, "Duisburg-Buchholz, Germany, assignor 'to Rheinstahl Wanheim Gesellschaft mit beschrtinkter Haftung Original application May 23, 1955, Serial No. "510,363. Divided and applicatinAug'ust 27, 1956, Serial No. 609,341. In Germany October 1, 1948 lf iblicl-iaw 619, August 23, 1954 7 Patent expires Octoberl, 1968 6 Claims. "(CL 248-357) The present invention relates to pit props of the type used'in mines for supporting top beams against the roof offa mine'shaft.

"One of the objects of the present invention is to provide pit props which are adjustable in length.

A further -object of the present invention is to provide a pit jprop 'with'an outer prop part receiving a plurality of 'inn'er'prop parts which are longitudinally movable relative to each other.

A further object of the present invention is to provide a pit prop with a'cap member which is capable of remaining in operativeengagement with relatively movable prop parts after one "of'such movable prop parts moves withrespect to one or more'othe'r prop parts.

With the 'above'objects in view, the present invention mainly (501181815012. pit prop which includes an outer hollow prop member and a pair of elongated channels forming inner 'prop members, spaced from each other, extending partly into the outer pro'p member, and being -'subst'antially parallel to each other. The inner'prop members are longitudinally movable relative to each other and independentlyof eachother, and a cap member is car- 'ried "by the inner prop members at theirtop end portions. A means is provided for maintaining the cap' member in engagement with the inner prop members even after one of the same :moveslongitudinally with respect to the other of the inner prop members.

The novel features whichare considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both United States I Patent as to its construction and its method of 'operation, tov gether' with 'additional objects and advantages thereof, will :bebest" understood from the following description of specific embodiments when read ,in connection with the accompanying drawings, inwhich':

Fig. l 'is a partly sectional elevational view showing the manner in which a cap member may be c'arried by a pit prop; and

Fig. 2 is a fragmentary sectional view showing a different embodiment of the manner in which a cap member may be supported at the top end of a pit prop.

Referring now to the drawings, Fig. 1 shows a pit prop composed of a plurality of elements which include a lower hollow outer prop member 16 having a closed bottom end adapted to engage the floor of the mine shaft and having an open top end. A pair of inner prop members 15 are parallel to and spaced from each other and extend into the hollow outer prop member 16.

As is evident from Fig. 1, a lock means 17 of known construction is carried by the outer prop member 16 for locking the inner prop members 15 with respect to each other and with respect to the outer prop part 16.

As was mentioned above, one of the great advantages provided by the arrangement of the invention is that the load may be distributed over a plurality of inner prop members which may be shifted longitudinally with respect to each other so that even when the prop cooperates "ice with inclined'fa'ce's of amine shaft 'or'the like,eccentric forces tending to bend the prop may be reduced -"to a minimum. The inner props -15 are formed'adjacent their top ends with openings 20 through which pins 19 extend with substantial clearance, these pins 19 being fixed to depending portions of the cap member-18 of 'theprop which engages the top beam. The bottom face of the cap member 18 has concavely curved portions respec tively forming sections of-cylinders, and the :to ends 0f the inner prop members 15 are respectively closed b'y members 21 which also form parts of cylinders, respectively, so that with-the arrangement of Fig. '-1 convexly curved top ends of props engage with conca'vely cnrved bottom face portions of the cap member 18, respectively. Thus, with the arrangement'of Fig. -1 either of the inner prop members may be lowered or raised with respect to the other prop member and the cap member 18will not interfere with such movement and will at thesam'e time remain in operative engagement with both .prop members.

According to the embodiment shown in Fig. Z'the bottom :face of the cap member 18' has concavely curved surface portions which form part of a single sphere. The top ends of the inner prop members 15 are closed by a pair of members 22 having top convexly curved surfaces formingpart of the same sphere, and thus with the embodiment of Fig. 2 the cap member can tilt-in all directions with respect to the inner prop members while re= maining in operative engagement with both-of the prop members even though the latter are'shifted longitudinally with respect toeach other.. As is shown in Fig. 2 the members 22 which close the prop ends of-the inner prop members 15 are interconnected with the prop members by a bolt 23 which extends with considerable clearance through openings of the prop'members 15' and mambers 22 so that the prop members are longitudinally shiftable with respect to each other within the limits determined by this clearance. ..The cap member 18'. has a pair of substantially triangulardepending portions interconnected by a pin 24 which extends freely between the inner prop members 15, so that in this ,way thecap member 18' does not interfere with the freedom of move ment of the inner prop members.

It will be understood that each of the elements described above, or two or more gtogether, may also find'a useful application in other types of props differing from v the types described above.

While the invention has been illustrated and described as embodied in mine props, it is not intended to. be limited to the detailsshown, since various modifications and structural changes may 'be made .without departing in any way fromthespir'it of the present invention.

Without further analysis, theforegoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

This application is a division of application Serial Number 510,363, filed May 23, 1955, and now abandoned.

What is claimed as new and desired to be secured by Letters Patent is:

1. A pit prop comprising, in combination, an outer hollow prop member; a pair of elongated inner prop members extending partly into said outer prop member, extending upwardly therefrom, and being substantially parallel to each other; means connecting said inner prop members to said outer prop member for longitudinal movement relative to and independently of each other; a cap member carried by and fastened to said inner prop members at the top end portions thereof; and means connected to said top end portions of said inner prop members and to said cap member for maintaining said cap member in engagement withsaid inner prop members andfor maintaining saidinner prop members in substantially parallel relationship even after one of said inner prop members moves longitudinally with respect to the other of said inner prop members.

2. A pit prop comprising, in combination, an outer hollow prop member; a pair of elongated inner prop members extending partly into said outer prop member, extending upwardly therefrom, and being substantially parallel to each other, said inner prop members each havinga curved top face; means connecting said inner prop members to'said outer prop member for longitudinal movement relative to and independently of each other; and a cap member having a bottom curved face engaging said curved faces of said prop members; and means connected to the top end portions of said inner prop member and to said cap member for maintaining said cap member in engagement with both said prop members and for maintaining said inner prop members in substantiaily parallel relationship even after one of said prop members moves independently with respect to the other prop member.

3. A pit prop comprising, in combination, an outer hollow prop member; a pair of elongated inner prop members extending partly into said outer prop member, extending upwardly therefrom, and being substantially parallel to each other, said inner prop members each having a convex top face; means connecting said inner prop members to said outer prop member for longitudinal movement relative to and independently of each other; and a cap member having bottom concave face portions respectively engaging said top faces of said inner prop members; and means connected to the top end portions of said inner prop member and to said cap member for maintaining said cap member in engagement with both said prop members and for maintaining said inner prop members in substantially parallel relationship even after one of said prop members moves independently with respect to the other prop member.

4. A pit prop comprising, in combination, an outer hollow prop member; a pair of elongated inner prop members extending partly into said outer prop member, extending upwardly therefrom, and being substantially parallel to each other; means connecting said inner prop members to said outer prop member for longitudinal movement relative to and independently of each other; a cap member carried by and fastened to said inner prop members at the top end portions thereof; and means connected to said top end portions of said inner prop members and to said cap member for maintaining said cap member in engagement with said inner prop members and for maintaining said inner prop members in substantially parallel relationship even after one of said inner prop members moves longitudinally with respect to the other of said inner prop members, said latter means including a portion of'each inner prop member overlapping a portion of said, cap member which extends downwardly alongside of said inner prop members, one of said portions being formed with a ,cutout and-the other of said portions carrying a pin extending with substantial clearance through said cutout.

5. A pit prop comprising, in combination, an outer hollow prop member; a pair of elongated inner prop members extending partly into said outer prop member, extending upwardly therefrom, and being substantially parallel to each other, said inner prop members each having a curved top face; means connecting said inner prop members to said outer prop member for longitudinal movement relative to and independently of each other; and a cap member having a bottom curved face engaging said curved faces of said prop members; and means connected to the top end portions of said inner prop member and to said cap member for maintaining said cap member in engagement with both said prop members and for maintaining said inner prop members in substantially parallel relationship even after one of said prop members moves independently with respect to the other prop member, said engaging faces of said cap memher and inner prop members being spherical.

6. A pit prop comprising, in combination, an outer hollow prop member; a pair of elongated inner prop members extending partly into said outer prop member, extending upwardly therefrom, and being substantially parallel to each other, said inner prop members each having a curved top face; means connecting said inner prop members to said outer prop member for longitudinal movement relative to and independently of each other; and a cap member having a bottom curved face engaging said curved faces of said prop members; and means connected to the top end portions of said inner prop member and to said cap member for maintaining said cap member in engagement with both said prop members and for maintaining said inner. prop members in substantially parallel relationship even after one of said prop members moves independently with respect to the other prop member, said engaging faces of said cap member and inner prop members being cylindrical.

References Cited in the file 'of this patent UNITED STATES PATENTS 776,881 Ambrose Dec. 6, 1904 891,897 Astrom June 30, 1908 FOREIGN PATENTS 571,643 Germany Mar. 3, 1933 828,086 Germany Jan. 14, 1952 

